Urinary Supersaturation with Calcium Oxalate Before and During Orthophosphate Therapy

Abstract

The concentrations of Na, K, Ca, Mg, P, SO4, citrate and oxalate in the urine of normal subjects were compared to the concentrations in urine of calcium oxalate stone-forming patients. Because of the large volume excreted by stone-forming patients the urine contained lower concentrations of Na, K, Mg, P, SO4 and citrate than did the urine from normal subjects. The urinary concentrations of Ca and oxalate were similar in the 2 groups and the calculated supersaturation of calcium oxalate was greater in the urine of stone-forming patients than in the urine of normal subjects. Pi therapy increased the urinary concentration of alkali ions and PO4 but reduced urinary Ca concentration, causing a reduction in urine supersaturation with calcium oxalate. There was no discernible correlation between the PO4 induced changes in urine supersaturation and the presence or absence of continued calculus formation.